Summary Mouse genetic engineering projects at GEC this year covered the following scientific areas: 1) Human disease modeling: It is often desirable to have mutations of human genetic conditions replicated in mouse so that the diseases can be modeled. In the last year, several such models were developed at GEC in collaboration with investigators at NEI, NIDCD and NICHD. Age related macular degeneration (AMD) in human, which is often manifested as vision loss at older age, has been a subject of intense investigation. New candidate genes have been recently discovered by Dr. Anand Swaroops lab at NEI, and GEC has engineered the equivalent mutant alleles in mouse to provide genetic confirmation of the AMD candidate genes derived from GWAS. These include loss-of-function alleles of 5 new candidate genes. Additional allelic series of two missense mutations targeting the mouse Pnpla2 gene have also been constructed at GEC. Pathogenic variants of the Pnpla2 gene lead to human Oliver-McFarlane and Laurence-Moon syndromes manifested as trichomegaly, congenital hypopituitarism and retinal degeneration with choroidal atrophy. Similar disease models developed at GEC this year include new Cdc14a missense mutations and Tbc1d24 CKO allele for congenital hearing loss, and additional work on the Sp7 missense mutation for bone density disorders. 2) Functional genomic studies of genes predicted to be important in physiology and pathology: Most of the current genome editing projects are aimed at simply understanding the functions of various genes relevant to NEI, as well as other participating IC research programs. Work in this area currently includes the construction of multiple loss-of-function mutations such as genes involved in the visual cascade and in survival of cones and rods. During the past year, we have worked on 62 different gene targeting projects at various stages. Genotyping operation: GEC genotyping services aided total of 24 laboratories most of which are from NEI intramural program and some from NIDCD, NINDS, NICHD, and NIDDK. * isolated DNA from 17,279 mouse tail biopsy samples * performed 10,451 PCR reactions to genotype mice in the facility * acted on behalf of 5 laboratories sending mouse tissue samples to Transnetyx for genotyping services. Cryopreservation and rederivation operations: GEC Cryopreservation services assisted total of 20 laboratories from NEI, NIDCD and NICHD. * Accomplished 106 projects of mouse cryopreservation, rederivation, rescuing, and speed expansion. *Accomplished 4 projects of Zebrafish cryopreservation.